Method of and apparatus for burning oil



June l 19H26.

F, c. STARR METHOD OF AND APPARATUS FORv BURNING OIL Filed oct. 25. 1922v lHlll lll l e:

/a TTORNEY Patented June 1,' 1926.

UNiTEDsrAjres PATENT 1 oFFicEf.

FLETCHER COLEMAN `STARRa oP PHILADELPHIA, PENNSYLVANIA, AssI'GNoR To iRrNGsLnY L. MARTIN, or MoNTcLAIR, NEW JERSEY.

METHOI) or AND APPARATUs PoR BURNING on..

-Alpiie'aaon aiea'october 23, 1922. 'serial' No. 596,275.

lThis invention relatesto -a method.v and apparatus especially intendedor 'adapted for burningoil and 'other liquid orsemiliquid `fuel, andaims to providea method and apparatus of greater flexibility and siii-'-ciency than the methods and apparatus heretofore used. rThe inventioncomprises' a '.method wherein'the'oil'or other liquid fuel is atom-"ized by means ofv 'steam or air or other suitable gaseous i mediumunder pressure and dischargedin. the form of a hollow cone,

.and the invention includes also apparatus for practicing the method.

Before my invention, oil has been burned efciently inboiler furnaces andother fur-4 naces in two ways, that is, by the use of mechanicalatomizers by which the oil is discharged in theforin of a hollow cone towhich air is supplied from a register or adjustable airinlet meanssurrounding the atomizer,'and `by the use ofsteam or air atomizers b ywhich the atomized oil `1s discharged with the steam or air in solidsprays of variousl forms. The' use of steam atomizers for spraying theoil has important advanta es over the use of mechanical. n-the otherhand, the spray? apparatus. i ing of the oil in the form of a hollowcone from a mechanical atomizer set in an air register has certainadvantages over the use of solid sprays.

The method andapparatus. of the present invention combines advantages ofboth me'- chanical atomization and steam or air atomization by sprayingthe fuel in the form of a hollow cone from a steam or air atomizer setin an air register or inlet pas-A sage through'which air for supportingcombustion is'admitted to the outer side of the spray cone. In burningAoil in this way there is secured also certain additional advantageswhich are not obtained with either of the old methods.. The oil burningcapacity 'of the burner apparatus under an available draft is greatlyincreased because of the greater permeability of the spray which permitsthe air to penetratethe cone wall and mix with the 'fuel more readily,and because of the greater voluine and sustained velocity' of the spraywhich tends to increase the air iiow. Also the spray cone retains itsrshape or angular width, and the same fineness. of atomization may bemaintained, through a very wide capacity range, thus panyin'g 4drawingsillustrating an oil burninsuring `proper air mixture ina given size iburner opening in' the furnace wall throughout a wide rangeiof capacity.

A full understandingof theinvention can ',best be given by a detaileddescription of an apparatus of approved form made in accordance with theinvention, andthe operation thereof, and such a description will now begiven in connection with the accomthe form of a hollowconefiniaccordance with the invention;

, Fig 2 is a View of the frontend of. the atomizer shown in Fig. 1; i

Fig. '3 isa sectional view of', an cil burning apparatus comprising anatomizing device suchas shown in Figs. 1 and 2 set in an air registermounted in a burner opening in a furnace Wall; and

Fig. 4 is 'a front view of an yorifice plate having a modified forni oforifice.

Fig. 5 illustrates another'form of orifice.I Y

Referring to the drawings, the atomizing device comprises a body 10formed with an opening orbore extendinginward from its front end inwhich is fitted aremovable plug 11 formed with a throat or passage'12opening from its rear end and an enlarged chamber 13 in its -forwardportion, the throat 12 opening into the chamber 13 and the chamber 13opening through the' front end of the lug.k The rear portion of the plug11is ot reduced diameter' so as to provide an annular chamber 14 withinthe body 10. The body 10 is also formed with a central opening-orchamber15, the forward wall of which is formed by the rearend of the plug11'and from which the passage or throat 12 opens. From the chamber 15 abore or opening extends to the rear end of the body 10, the inner end ofwhich bore is of reduced diameterand threaded to receive .a nozzle 16,andthe outer end of which is fuel is,v supplied-to the'chamber 15. froma n P 'supply pipe 21. 1 Steam or air or other gaseous ,medium underpressure is. supplied through a supply pipe 22 to an inlet passage23formed in the body 10 and 'which communicates through a port 24 withthe chamber 18 and also communicates with the` passage 14. A capor-plate 25 held against the front end of the body by means of a ringnut 26 forms the front wall of the mixingchamber 13 and is provided inthe apparatus shown withv a Aplurality of discharge orifices 30.

The liquid fuel, which may be fuel oil or crude. oil or .other suitableoil or tar or other suitable liquid or semi-liquid fuel, is supplied tothe inlet passage 20" under pressure sufficient-to maintain a supply ofthe fuel liquid in the chamber 15. The nozzle 16 and throat or passage12are arranged in axial alignment, and the rear or entrance end ofthethroat is somewhat flared and the nozzle is set to extend into thechamber 15 andsuita'bly close to the flared entrance end, or entrancecone, of the throat, so that the jet of steam or other gaseous mediumdischarged from the nozzle into the throat will act to induce flow ofthe fuel liquid from the chamber 15 into the throat and to drive thesame thrdugh the throat into the chamber 13. The fuel liquid thus driventhrough 4the throat 12 by the jet of steam or other gaseous medium isthereby broken up or partially atomized and mixed with the atomizingmedium.

Leading from the annular passage 14 are a plurality of small passages orports 35 vfor discharging jets of the steam or other gaseous atomizingmedium into the chamber 13 for further atomizing the fuel liquid andmaintaining the fluid in the chamber 13 in motion and the finelydivided, or atomized, fuel liquid in suspension in' the gaseous medium.These ports 35 are most desirably arranged to deliver the atomizingmedium in a direction more or less tangential to the stream of atomizingmedium flowing from the throat 12 so as to impart a whirling motion tothe body of atomizing medium in the chamber 13 with its atomized fuel insuspension therein; and the discharge ends of these ports are mostdesirablv locatedlat the end of the passage'12 so that the jets issuingtherefrom will be directed into the chamber 13. and will strike thestream of atomizing medium and partially atomized fuel as it flows fromthe passage 12 into the chamber 13. The vatomizing medium withy theatomized fuel carried therebyT is discharged through the dischargeorifices 30.

lt will be noticed that as shown in Fig. 1 the rear wall of the chamber13 extends outwardly at right angles from the wall of` the passage 12.Having the rear wall of the chamber'extend away from the end of thepassage at approximately a right angle seems to have an effect insecuring albetter j atomization at this point. l

ln the operation of the atomizer, a body of the gaseous atomizing mediumunder pressure is maintained in the chamber 13 with the finely divided,or atomized, fuel in suspension therein, gaseous mixture from this bodyconstantly being discharged /through the discharge orifice or orifices,and the body being constantly renewed by the stream from the throat12and jets from the ports 35 in the form of atomizer shown. By suitablearrangement of the discharge orifice or orifices, the spray dischargedfrom the chamber 13 may be given practically any desired form. Not onlymay solid sprays of various forms be produced, but a spray in the formof a hollow, and hollow cone y sprays of other forms having relativelythin walls, may also be produced.

A hollow cone spray may lbe .produced by providing the chamber 13 withathin front wall such as the cap 25 shown in Figs. 1 and 2, of outwardlybulging form and pro,- vided with an annular or circularly arrangedseries of discharge orifices 30 arranged concentric with the axis orcenter line of the burner. The gaseous medium with the atomized fuelwill. be discharged through -.these orifices in a'series of outwardlydirected separate jets which as they expand merge together and form ahollow conical spray. The angular width of the spray cone'will dependupon the arrangement of f the orifices, and the thickness of the conewall will depend upon the size of the orifices. In the device shown, inwhich the orifices 30 are formed i'n` a thin cap plate, the direction ofthe individual jets and the Y angular width of the spray cone will bedetermined. by the angle to the burner axis of the part of the innerwall of the cap plate in which the orifices are located, since thedirection of the pressure of the fluid at the orifice will determine thedirection of the jet. The invention is, however, of course not limitedto the use of a vthin orifice plate having av curvature which determinesthe jet direction, as the orifice may be otherwise formed to givethe-desired angular direction to the spray.

rl`he series of orifices 30 arranged as shown may be considered as anannular orifice divided into a plurality of separate discharge openingsfor the purpose of producing a plurality of circularly arrangedseparate(but closely spaced jets which at a short distance beyond the orificeplate unite to form a closed or Vcircumferentially continuous spray conewall. The use of a series of closely spaced separate openings hascertain advantages, but the invention is, of course` not limited to theuse of such a divided orifice, and an orifice formed of one or moreslots might, of course, be employed. Fig.

4 shows, for example, an orifice plate having an annular orifice formedby three slots 30. f. l y 4 Combustion air is most desirably supplied tothe hollowl cone spray, by setting the spray nozzle or atomizer in anair register,

or air inlet opening, for supplying a flow' of air againstthe outsideofl the cone in the saine manner as is the practice with mechanicalatomizers producing hollow cone sprays. An arrangement 1s illustrated 1nFig. 3 which shows an atomizer A ofthe construction shown byvFigs. l and2 set inthe center. oflan air register B mounted on a furnace.

Wall 40 with the atomizer in position to discharge its spray conecentrally through a burner opening in the wall. The burner` opening isprovided with a tire-brick ring' 41 of suitable form,.-and the4 lsize ofthe burner opening through the rin-g 41 and the position of theatomizer'is such that the spray cone will substantially till the'opening without having the sprayed fuel strike against the wall of theopening, or surface of the ring 41. Theair register or means foradmitting air 'around the atomizer under the suction of the furnacedraft, or, as it might be, under forced draft, may be of any suitableconstruction. An'air register o'f known form is sho-wn constructed toprovide a main annular air inlet 42 and a series of inlet openings 43immediately about and extending in close to the atomizer. An ad.`justable plate 44 having openings .cor-responding to the air inletopenings 43`may be provided for adjusting'theeifective size of theopenings 43; and adjustably. pivoted .shutters 45 may be provided forcontrolling the amount of air entering through the main air inletpassage42, and for givlng the enter' ing air a revolving or spiralmovement. The

annular air inlet passage 42 is advantageous-y4 -ly shaped as shown todirect the air inward ly in a converging'streamagainst the spray cone,and the irebrick ring 41 is desirably y. curved toprovide a wallextending as a continuatio'n of the outer wall of -the vair registerlatomizing fuel by means o inward toward thepath of thespray cone, andthen outwardly, thereby providing a burner opening inpassing throughwhich the spray cone will exert a greater flow inducing action on theair than would be the case if the wall of the burner opening were not soformed. The invention is not,v however, limited to any particular formof burner opening.

The method of burnin gascous medium under pressure anddischarging themixture. of fuel and gaseous medium in the form of a hollow cone and'directing combustion supporting air against the outside of the cone, andapparatus comprising means for atomizing liquid fuel b-y'a gaseousmedium underA pressure and dischargingthe mixture in a liquid fuel byhollow cone spray set in an air register or than a steam atomizer set inan' air register and'discharging ahollow'cone spray. Com- 8 vair inletmeans for supplying air to the outimv parative tests haveshown that inso burning an equivalent amount of oil a steam atomizer burnerrequiresonly about -one-half to onetliird of the draft required by al mechanicalatoinizing burner. This greater capacity of the 'hollow cone spray steamatomizing burner is probably due to the greater diifusion of the oil inthe-spray andgreater permeability of thesteani and atomized oil spray ascompared tothe spray from a me chanical atomizer; and 4also to thegreater volume and higher sustained velocity of the steam atomized sprayresulting in stronger iiow4 inducing action on the entering air.

The wall of the s ray cone is also ermeable to the air consi erablycloser to t e discharge oriiice than is the case with a inechanicallyatomized hollow cone spray. This is so even if the spray is dischargedfrom an orifice in the form of a'continuous or uninterrupted slot, andwhenthe spray is discharged froin an oriceformed by a series of closelyspaced separate openings, as shown 1n Fig. 2, the open spaces betweenthe separate jets close Ato the oriiice plate afford opportunity forready entrance of air striking the spray at this point.

The burner construction of the present invention willalso operateetliciently through a much greater capacity-range than a burnerdischarging a mechanically atomized hollow cone spray. This greaterflexibility is due not only tothe characteristics?` of steam or airatomization which give a greater iieXiy bility in discharging the fueli-n a solid spray, but also to the fact that the hollow spray coneretains the saine angular width at all rates of oil consumption withinthe limits of the burner and furnace. The 4angular width of the cone ofa hollow cone spray Jfrom a Steam or air. atomiz'er is, as stated,'

fixed by the form and arrangement of the discharge orifices, and doesnot depend, as 4 is the case with the mechanical atomizer, on thevelocit)v of rotation and resulting centrifugal force. As in dischargingthe fuel in a solid spray from a steam or air atomizcr, so also iiidischarging the fuel iii-a hol-.v

low cone spray, the same fineness of atomization may be secured at allrates of oil consumption within the range of the apparatus.

It may be noted that when steam is employed as the atomizing medium,- orif other atomizing medium employed is preheated to 'a sufficient degree,the oil is more or less vaporized before being discharged from theatomizer. s

vA further very important advantage of the present invention i's that itis not limited to the production of a hollow spray which is annular incross-section, since by using discharge orifices of suitable shapesoutwardly spreading hollow sprays of vari- I ous forms in cross-sectionmay be produced.

of an outwardly spreading thin walled hol-` low spray, the fuel being ina finely divided condition 1n suspension 1n the gaseous medium, andcausing airto flow against the outer side 'of the spray .wall and toenter the same. f i

2. The method of burning liquid fuel, which comprises discharging amixture of the fuel and a gaseous medium in the form' of' a thin walledhollow conical spray, the fuel being in a finely divided condition insuspension in the gaseous medium, and causing air to flow against theouter side of the conical spray wall. and to enter the same.

3. The method of burning liquid-fuel, which comprises atomizing the fuelliquid by means of gaseous medium under pressure and discharging thegaseous medium with the atomized. fuel in suspension'therein in the formof an outwardly spreading thin .walled hollow spray through a burneropening of such size and form that the saray passes closely adjacent tothe wall o .the

burner opening, and thereby inducing a flow of air into the burneropening andv against the spray wall to enter the same and mingle withthe atomized fuel. Y

4. The method of burning liquid` fuel, which comprises maintaining underpressure a body of gaseous medium having finely divided fuel in.suspension therein, discharging the mixture of gaseous medium and fuelin a multiplicity of circularly arranged outwardly directed jets whichcombine to form aspray in the form of a thin walled hollow cone, anddirecting air against the outer side of said jets and sbrav cone.

mamas 5. Apparatus for burning liquid fuel, comprising means fordischarging a mixture of the fuel and a gaseous, medium in the form ofan outwardly spreading thinwalled hollow spray, the fuel being in afinely divided condition in suspension in the gaseous medium, and meansfor causing air to flow against the outer side of the. spray wall.

6. Apparatus for burning liquid fuel, comprising means for maintaining abody of gaseous medium under pressure with the fuel in a finely dividedcondition in suspension therein, meansproviding a discharge orificethrough which the mixture of gaseous medium and fuel is discharged inthe form of an outwardly spreading thin walled hollow spray, and meansfor causing air to fiow against the outer side of the spray.

' 7. Apparatus for burning liquid fuel, comprising means for maintaininga body of gaseous medium under pressure with the fuel in a fil' ilydivided condition in suspensionv therein, means providing an orificethrough which the mixture of gaseous medium and fuel is discharged inthe form of a thin walled hollow cone, and means for causing air to fiowlagainst the outer side of the spray cone.

8.. Apparatus for burning liquid fuel, which comprises means formaintaining a body of gaseous medium under pressure withthe fuel in afinely divided condition in suspension therein, means providing adischarge orifice formed by a series of separate closely spacedcircularly arranged openings for discharging the mixture of gaseousmecausing air to flow against the outer side of the Spray cone.

9. Apparatus for vburning liquid fuel, comprising an air registermounted on a furnace wall having a burner opening therein extending fromthe air register; and an atomizing device set in the air registercomprisinga chamber having a discharge orifice opening from the frontthereof, and means for supplying to and maintaining within the chamber abody of gaseous medium under pressure with the fuel in a finely dividedcondition in suspension therein, the discharge orifice being formed todischarge the mixture of gaseous medium and fuel from thechamber in theform of an outwardly spreading thinvwalled hollow spray which passesclosely adjacent to the wall of the burner opening and is ofcross-sectional form corresponding to the shape of the burner opening.

lntestimony whereof l have hereunto set my hand.

llO

